Cu Nanoclusters: Novel Electrochemiluminescence Emitters for Bioanalysis.

Cu nanoclusters (Cu NCs), which emerged as a new class of nontoxic, economic, and excellent phosphors and catalysts, have attracted increasing interest for a wide variety of promising applications in biolabeling and biocatalysis. However, the electrochemiluminescence (ECL) behavior of Cu NCs has never been reported in previous works. Here, anodic and blue ECL emission of Cu NCs was observed for the first time with the efficient coreactant of hydrazine (HZ), and the possible luminescence mechanism of Cu NCs/HZ ECL system was studied in detail. Briefly, HZ was oxidized, and Cu NCs got the energy to generate excited state Cu NCs* for light radiation. Furthermore, a highly sensitive "signal-off" sensing platform for the determination of dopamine has been developed upon effectively quenching of dopamine toward the Cu NCs/HZ-based ECL system. As a result, this proposed method for dopamine detection possesses high selectivity, good stability, and excellent sensitivity with a detection limit down to 3.5 × 10-13 M. This indicates that Cu NCs show potential for applications in ECL bioanalysis as a new type of low-cost and superior luminophore candidates.